Figure 5

Characteristics of age-associated DNA methylation signature. (A) Age prediction using the age-associated normal DNAm signature. Age was predicted with the normal signature using a multivariate linear regression after using a genetic algorithm to identify a feasible set of loci. (B) Degrees of overlap with age-associated DNAm signatures identified in previous studies. Overlap percentages were calculated by the common numbers divided by the smaller number of total loci in either study. The studies with only normal samples are orange; other studies including disease samples are gray. (C, D) The fractions of hyper- (green) or hypomethylated (blue) CpG loci in the age-associated signatures in normal (C) or cancer (D) according to genomic regions. The number on each bar indicates the count of the corresponding loci. P-value was calculated by a chi-square test. (E, F) The hyper- (E) or hypomethylation (F) patterns according to age group of normal age-associated DNA loci in CGI or non-CGI. Blue or green dotted lines show the linear regressions of median values of individual age groups using only hypo- (blue) or hypermethylated (green) loci, respectively. Numbers below are the counts of loci considered for the corresponding cases. (G, H) Nucleotide compositions of the sequences surrounding the hypo- (G) or hypermethylated loci (H) of normal age-associated DNAm signature. –log (P-value) of the y axis was calculated by random selection tests representing overrepresentation for each base at each location of the surrounding CpG.